[maemo-developers] [maemo-developers] Speed test with vfp (floating point) on N800

[From: Kalle Vahlman]

2007/2/12, Simon Pickering <S.G.Pickering at bath.ac.uk>:
>
> > I was very interesseted in the floating point copro in the
> > N800 cpu and did some tests with a progamm which calculates
> > the mandelbrod set and outputs it via SDL. I put this program
> > online on bomberman.garage.maemo.org. No installer, you have
> > to run the benchmarks on xterm or via ssh (so did I).
>
> For reference, I've also got some benchmark results. I compiled whetstone, flops
> and dhrystone (and paranoia) for the 770, N800 and my desktop PC (for
> comparison).
>
> Results here:
> http://people.bath.ac.uk/enpsgp/benchmarks/N800-fp-tests.txt
> http://people.bath.ac.uk/enpsgp/benchmarks/770-fp-tests.txt
> http://people.bath.ac.uk/enpsgp/benchmarks/PC-fp-tests.txt
>
> Binaries here:
> http://people.bath.ac.uk/enpsgp/benchmarks/
>
> My apologies for the layout of the txt files, I'm in the process of tidying them
> up and putting up a results page.
>
> Curiously the 770 performs better for dhrystone with optimisation than the N800,
> but these results were variable and should probably be run with a very large
> number of iterations to produce less variability.
>
> As expected, flops was far faster for the vfp code run on the N800 and slightly
> faster for the softvfp code run on the N800 compared with the 770 (due to
> processor speed difference).
>
> The whetstone results were a little surprising, in that the vfp code wasn't
> orders of magnitude faster than the softvfp code as expected, however this is
> probably (as a guess) caused by libm not being compiled for vfp.

Indeed, I ran these with a vfp libm and the results speak for themselves:

./whetstone.vfp.O0.out

Loops: 1000, Iterations: 1, Duration: 7 sec.
C Converted Double Precision Whetstones: 14.3 MIPS
---
./whetstone.vfp.O1.out

Loops: 1000, Iterations: 1, Duration: 3 sec.
C Converted Double Precision Whetstones: 33.3 MIPS
---
./whetstone.vfp.O2.out

Loops: 1000, Iterations: 1, Duration: 2 sec.
C Converted Double Precision Whetstones: 50.0 MIPS
---
./whetstone.vfp.O3.out

Loops: 1000, Iterations: 1, Duration: 2 sec.
C Converted Double Precision Whetstones: 50.0 MIPS
---
./whetstone.vfp.Os.out

Loops: 1000, Iterations: 1, Duration: 3 sec.
C Converted Double Precision Whetstones: 33.3 MIPS
---

-- 
Kalle Vahlman, zuh at iki.fi
Powered by http://movial.fi
Interesting stuff at http://syslog.movial.fi